IS NULL Conditional Expression

Description

The IS NULL conditional expression compares to determine whether the expression specified on the left is NULL, and if it is NULL, returns TRUE and it can be used in the conditional expression. If NOT comes before the NULL keyword, the result of a NOT operation on the result of the IS NULL operation is returned.

Syntax

expressionIS [ NOT ] NULL

expression : A single-value column, path expression, constant value or arithmetic function that produces a single value can be used.